fix: 输入校验忽略多个连续空格与大小写；统一中英文引号与空白规范化

kouyu_english/lib/core/assessment_bank.dart

@@ -155,12 +155,31 @@ AssessmentPack? replacementFor(String packId) => switch (packId) {
 /// Local checks for the frozen A0 exit tasks. They accept variable names and
 /// places, but require the communicative information named by each task.
 bool checkOpenAssessmentAnswer(AssessmentTask task, String input) {
-  final text = input.toLowerCase().replaceAll('’', "'");
+  final text = input
+      .toLowerCase()
+      .replaceAll('’', "'")
+      .replaceAll('‘', "'")
+      .replaceAll(RegExp(r"\s+"), " ")
+      .trim();
   final words = RegExp(
     r"[a-z]+(?:'[a-z]+)?",
   ).allMatches(text).map((match) => match.group(0)!).toSet();
-  bool has(String word) => words.contains(word);
-  bool phrase(String value) => text.contains(value);
+  bool has(String word) => words.contains(
+    word
+        .toLowerCase()
+        .replaceAll('’', "'")
+        .replaceAll('‘', "'")
+        .trim(),
+  );
+  bool phrase(String value) {
+    final normVal = value
+        .toLowerCase()
+        .replaceAll('’', "'")
+        .replaceAll('‘', "'")
+        .replaceAll(RegExp(r"\s+"), " ")
+        .trim();
+    return text.contains(normVal);
+  }
   bool hasAny(Iterable<String> values) => values.any(has);
   final introduction = phrase("i'm") || phrase('i am') || phrase('my name is');
   final itIs = phrase("it's") || phrase('it is');